Widening my approach

It's 12MP cropped (exact same as the A700). Don't use it. It's just limiting yourself. Just take the big picture and crop as needed.

Basically ... going to "CROP" mode allows for a tighter and shallower DOF, in my calculations. A little flexibility, there, that may be worth consideration. I mean, at least YOU can play with it (at the same f/stop setting) ... I'm stuck at APS-C sensor widths with my PRIMES. LOL :rolleyes: It's not going to change. If I use a 2x T/C ... I lengthen the lens, but I also change the base f/stop two f/stop tighter, e.g., f/1.8 -> f/5. What a waste of a prime, eh?

Cropping in PP with the crop sliders is no different than switching to crop mode so I'm not sure how the DOF would change. I don't own an A900, but from what I've read it's identical.

NOT according to the DOF calculator, Ryan. If (big IF here) the "A900 Crop" reproduces the APS-C sensor results ... then it may be the case as I have stated. If "Crop" mode simply narrows the image ... then, it may not. I kind of wish I had one to try it out, before stepping in it. :o

I would suggest you take a peek at it and do some exercises with various settings. Makes sure you specify the camera ... there are the APS-C sensors and and A900. They are different and "A900 Crop Mode" is not specified, per se.

Maybe I should get an A900. Oh heck, there's always the SONY Style store ... they have one laying around, not doing much. Most people see that sticker price and recoil in horror! :eek:

I'm not 100% clear on the diagrams, but the FOV lessons obviously as you go from 1x to a 1.5x crop. The DOF can't possibly change because the crop is done in PP and I don't see how the A900's sensor size is changing. If it physically changed by using an aperture to block off light, then I could see that but I don't think that's how it works.

Well ... erring on the side of caution ... until I am absolutely sure, I will go with your supposition that the A900's DOF does NOT change when switching to "crop."

I have made the edit to the overlay drawing ... taking the "A900 Crop" out of the diagram.

Thanks for the catch, Ryan. :D ... there is just no sense putting ambiguous or improper info out there. It is bad enough that SONY doesn't offer that kind of relevant information in their associated USER manuals. Hey, they put the capability in the camera. :rolleyes:

Quote:

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Originally Posted by DonSchap

NOT according to the DOF calculator, Ryan. If (big IF here) the "A900 Crop" reproduces the APS-C sensor results ... then it may be the case as I have stated. If "Crop" mode simply narrows the image ... then, it may not. I kind of wish I had one to try it out, before stepping in it. :o

I would suggest you take a peek at it and do some exercises with various settings. Makes sure you specify the camera ... there are the APS-C sensors and and A900. They are different and "A900 Crop Mode" is not specified, per se.

Maybe I should get an A900. Oh heck, there's always the SONY Style store ... they have one laying around, not doing much. Most people see that sticker price and recoil in horror! :eek:

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I'm trying to think about how to test it. I'm tempted to attach my Sony 50mm f/1.4 to the A900, set it on Aperature priority mode at f/1.4 and take two identical photos, one full frame and one APS-C to see if there's any change in DOF. Think it'll work:confused:

Quote:

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Originally Posted by DWessel

I'm trying to think about how to test it. I'm tempted to attach my Sony 50mm f/1.4 to the A900, set it on Aperature priority mode at f/1.4 and take two identical photos, one full frame and one APS-C to see if there's any change in DOF. Think it'll work:confused:

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Focus on something close by, use a tripod and shoot in both modes, post up the full results!

According to Don's guess, the bokeh (DOF) should be different between the two in the cropped area.

I believe the two should be identical. The cropped picture will just be an identical fraction of the larger full-frame image.

Here's an idea with the 50mm set at f/2.8, not f/1.4 ... which may be too shallow to adequately determine a difference.

These numbers allow seeing a real change in image. Use a tape measure and shoot along it, placing items (colored blocks)
at the specified "N/C" extreme (Close/Far) distances. You should clearly see a change, if it does change.

10-feet

A900 . . . . Lens . . . . . Aperture . . . . DOF Width . , , Close . . . . . Far

Crop . . . . 50mm . . . . . f/2.8 . . . . . . . 1.36 ft . . . . . 9.36 ft . . . 10.7 ft

N/C . . . . .50mm . . . . . f/2.8 . . . . . . . 2.06 ft . . . . . 9 ft . . . . . 11 ft



20 –feet

A900 . . . . Lens . . . . . Aperture . . . . DOF Width . , , Close . . . . . Far

Crop . . . . 50mm . . . . . f/2.8 . . . . . . . 5.6 ft . . . . . 17.6 ft . . . . 23.2 ft

N/C . . . . .50mm . . . . . f/2.8 . . . . . . . 8.6 ft . . . . . 16.6 ft . . . . 25.2 ft

.
.
N/C = Not crop (normal mode)

Attachment 46727

Oh Boy! Are you guys getting your knickers in a twist or what.
If you take a pic with an A900 camera and crop it in Photoshop, the DOF won't change.
That's all the crop mode does on camera. Ergo the DOF is the same.